Multi-purpose piston valve

ABSTRACT

A pneumatically controllable, two-way fluid shut-off valve convertible to either of three normal operating states. A housing includes a tubular sidewall defining a chamber elongated between first and second chamber ends, a ring-shaped spring stop is affixed in sealing relation around the inside of the sidewall spaced away from and adjacent to the first chamber end. The housing also includes an end cap connected to the sidewall at the first end of the chamber and comprises a first input/output port, a separating wall in between the first port and the chamber and at least one passage between the chamber and the first port and a second end cap removably affixed to the sidewall at the second end of the chamber. The second end cap has a second ring-shaped spring stop extending into the chamber and a second input/output port extending from the exterior to the chamber. A removable tubular-shaped shut-off piston is mounted in the chamber having a ring-shaped third stop affixed in sealing arrangement around the piston intermediate the ends thereof. The piston has a second end slidably mounted in the second port and the first end is adapted for sealing engagement with the separating wall. The piston is slidable between a shut-off position against the separating wall and an open position spaced away from the separating wall. The first, second and third spring stops are positioned and constructed to leave space for a compressed bias spring on either side of the third stop, regardless of the position of the piston. Separate sliding seals are provided in between the third stop and the sidewall, in between the first stop and the piston and in between the second port and the piston. First and second pneumatic control ports, respectively, pass through the housing to the chamber at a position which is on opposite sides of the third stop regardless of the position of the piston.

United States Patent [1 1 Roth et al.

[ 51 Jan. 9, 1973 [54] MULTI-PURPOSE PISTON VALVE [76] Inventors: Verlon C. Roth; Arden J. Roth, both of 2279 Trinway Avenue, Simi Valley, Calif. 93065 [22] Filed: June7,1 97l 21 Appl.No.: 150,454

[52] US. Cl ..l37/271 [51] Int. Cl ..F16k 31/58 [58] Field of Search...l37/269, 270, 270.5, 271, 228;

[56] References Cited UNITED STATES PATENTS 2,200,824 5/1940 Herman ..l37/270 2,656,846 10/1953 Anderson ....l37/270X 3,026,896 3/1962 Bosworth et al ..l37/270 Primary Examiner-M. Cary Nelson Assistant ExaminerRobert J. Miller AttorneyChristie, Parker & Hale [57] ABSTRACT from and adjacent to the first chamber end. The housing also includes an end cap connected to the sidewall at the first end of the chamber and comprises a first input/output port, a separating wall in between the first port and the chamber and at least one passage between the chamber and the first port and a second end cap removably affixed to the sidewall at the second end of the chamber. The second end cap has a second ring-shaped spring stop extending into the chamber and a second input/output port extending from the exterior to the chamber. A removable tubular-shaped shut-off piston is mounted in the chamber having a ring-shaped third stop affixed in sealing arrangement around the piston intermediate the ends thereof. The piston has a second end slidably mounted in the second port and the first end is adapted for sealing engagement with the separating wall. The piston is slidable between a shut-off position against the separating wall and an open position spaced away from the separating wall. The first, second and third spring stops are positioned and constructed to leave space for a compressed bias spring on either side of the third stop, regardless of the position of the piston. Separate sliding seals are provided in between the third stop and the sidewall, in between the first stop and the piston and in between the second port and the piston. First and second pneumatic control ports, respectively, pass through the housing to the chamber at a position which is on opposite sides of the third stop regardless of the position of the piston.

7 Claims, 1 Drawing Figure MULTI-PURPOSE PISTON VALVE BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a pneumatically controlled valve and more particularly to improvements in valves having pneumatically controlled pistons.

2. Description of the Prior Art Pneumatically operated. control valves are known having a housing and an elongated, generally cylindrical-shaped chamber in which a matching piston is positioned for axial movementin the chamber. The piston has a passage coaxial with the chamber which extends from one end of the piston to the other. The chamber has a seat at one end against which the endof the piston rests when the valve isshut off. An input/output port is positioned at each end of the housing coaxially with the chamber. A number of passages extend from one of the ports through the chamber around the edges of the seat. The other port is connected directly into the chamber.

Seals are provided in between the inside of the chamber and the piston, allowing the piston to move from one end of the chamber to the other and preventing fluid coming in either of the ports from passing along the outer side of the piston.

The piston has an outer raised portion of larger diameter than the rest Of the outer portion of the piston. Two control portsare provided through the housing wall into the chamber. Pneumatic pressure applied in one of the control ports acts against the raised portion of the piston actuating it to one position whereas pressure applied in the other control port acts againstthe other endof the raised portion actuating the piston to an open position.

SUMMARY OF THE INVENTION The present invention is directed to an improvement in such pneumatically actuated control valve. In accordance with the principles of the present invention, a pneumatically controllable two-way fluid shut-off valve is provided which is convertible to three normal operating states. The three normal operating states are normally shut-off, normally open or a condition where pneumatic pressure is required to reliably hold the valve in either a shut-off or anopen state. A' housing is provided having a tubular sidewall defining a chamber. A first ring-shaped spring stop isaffixed in sealing relation around the inside of the sidewall and spaced away from the first chamber end. The housing includes an end cap connected to the sidewall at the first end Of the chamber-having a first input/output port, aseparating wall positioned in between the first port and the chamber and at least one passage between the chamber and the first port. Also in the housing is an end cap removably affixed to the-sidewall at the second end of the chamber having a second ring-shaped'spring stop extending into the chamber and-a second input/output port extending from the exterior to the chamber. A removable tubular-shaped shut-off piston elongated between. first and second ends is mounted in the chamber. The piston has a ring-shaped third stop affixed in sealing arrangement around the piston and intermediate the ends thereof. The piston has a second end slidably mounted in the secondport and the first end is adapted for sealing engagement with the separating wall. The passage around the separating wall enters the chamber on the outer side of the piston and the piston is slidable between a shut-off position against the separating wall and an open position spaced away from.

the separating wall. The first, second and third spring stops are positioned and constructed to leave space for a compressed bias spring on either side of the third stop when the piston is in the open or in the shut off position. Separate ring-shaped means are provided for slidably mounting and providing a sliding fluid seal, respectively, in between the third stop and inside of the sidewall,- in between the first stop and the piston and in between the second port and the piston. First and second pneumatic control ports, respectively, pass through the housing to the chamber at positions which are at opposite sides of the third stop, whether the piston is in the shut-off or in the open position.

A number of important features flow from the foregoing invention. First, it is possible to bias the piston to a normal open position by placing a coil spring in between the first and third stops. Alternately,

if so desired, it is possible to bias the piston to a normally closed position by placing the coil spring in between the third and second stops. With thespring in either position, the valve is easily actuable to the opposite condition i.e., from an open to a shut-off condition or from an open condition to a, shut-off condition by applying pneumatic pressure to the appropriate control port. An additional feature of the present invention is that the valve-is very easily converted from one normal bias condition to the other by merely removing the removable end cap, sliding the piston and spring out of the end cap and changing the side of the third stop on which the spring is positioned. If it is desired to convert the valve to one which is not biased either to a normally open or a normally closed position, one merely removes the spring.

A further advantage of the present invention is its simplicity and low cost of manufacture which facilitates the multi-purpose operation of the valve.

A further feature of the present invention is the ease of operation. The above-described prior art valve is arranged so that the raised portion of the piston passes over and substantially blocks the pneumatic control ports. As a result, the effect of the pneumatic pressure applied through the control ports to the piston is reduced. This condition is not possible with the preferred embodiment of the invention;

BRIEF DESCRIPTION OF THE DRAWING These and other aspects and advantages of the present invention are more clearly defined and described with reference to the drawing which shows a half section view of the 'multi-purpose piston valve taken parallelwith the axis of the valve. The part of the valve cut away is a mirror image of the part shown.

DESCRIPTION OF THE PREFERRED EMBODIMENT I Referring to the drawing, the multi-purpose piston valve in accordance with the present invention includes a generally round, cylindrical-shaped housing shown generally at and a piston shown generally-at 200. The housing 100 has a circular, tubular-shaped sidewall 110 defining a circular, cylindrical-shaped chamber 112 elongated from a first end 1120 to a second end 112b. A first circular, ring-shaped spring stop 114 is affixed in sealing relation completely around the inside of the sidewall in the chamber. The spring stop 114 is adjacent to the first end of the chamber but is spaced away slightly to enable fluid flow from the adjacent port as will be explained in more detail hereinafter. A circular end cap 116 is permanently affixed by molding or cement in sealing relation around the inside of the tubular sidewall 110 at the first end of the chamber. The end cap 116 has a first input-output port 118 and a separating end wall 120 which is positioned in between the first port and the chamber. Eight passages 122 (only two being shown in the drawing) diverge outwardly from the first port 118 into the chamber 112, passing through separating wall 120. To be explained in more detail, the passages 122 diverge outwardly toward the chamber in order to enable the piston 200 to seat against the inside surface 1200 of the end wall !l20 at a position inwardly from the entry of the passages 122 into the chamber 112.

And end cap 124 is affixed to the second end 112b of the sidewall. The end cap 124 and the sidewall 110 having mating threads 125 which allow the end cap 124 to be screwedinto and screwed out of the tubular sidewall 110. The end cap 124 has a circular, ring-shaped end forming a third spring stop 127. Spring stop 127 includes a circular, ring-shaped groove 126. To be explained in more detail, one end'of a spiral spring 128 is positioned into thegroove 126 for biasing the piston 200 into a shut-off position. The end cap 124 also has a smooth bearing surface l24b along which one end of the piston 200 slides. A circular and inwardly raised portion forms a stop 124b for movement of the piston 200 to the right and defining the complete open position of thepiston. The end caps 116 and '124 have internal threads and 116d and 124d into which pipe fittings can be threaded for passing fluid through the valve. A first control'port 132 having a threaded exterior end passes through the end cap 124 into the spring stop groove 128. To be explained in more detail, pneumatic pressure applied in the control port 132 actuates the piston 200 toward a shut-off position.

' The piston 200 is' an elongated, circular, tubularshaped shut-off piston elongated between the first and second ends 200a and 200b. The piston 200 has a tubular-shaped portion'202 with a passage 204 extending from the first to the second end. The piston 200 has a ring-shaped third spring stop affixed in sealing relationship completely around the outer diameter of the tube portion 202 at a position which is intermediate the ends 2000' and 200b.'Annular grooves 214 and 216 are positioned on opposite faces of the spring stop 210 to sup port one end of spring 300. The second end 200b of the piston 200 is slidably mounted on the bearing in the surface124a of the end cap .124. The first end 2000 of the piston 200 has a pair of concentric annular rings 20011 which seatagainst th6 '-l1 l8ld6 wall 1200 of the separating wall 120. To be explained in more detail, the end 200a of thepiston, when positioned against the flat inside wall 1200, forms a seal preventing fluid passing through the passages 122 from'entering the passage 204 through the piston 200. Circular rings 220, 222, and 224 are preferably made of a resilient material such as rubber, and have Teflon caps 222. The O-rings provide a sliding and yet fluid-tight seal in between the piston and the housing as explained in more detail hereinafter. The O-ring 220 is positioned in a groove in the tube 202 so as to providea sliding fluid seal in between the tube 202 and the stop 114. Similarly, the O-ring 222 is positioned in a groove around the outer diameter of the ring-shaped stop 210 so that it provides a sliding and fluid-tight seal between the stop 210 and the inner wall of the tubular sidewall 110. In a like manner, the O-ring' 224 is positioned in a groove in the tube 202 so as to provide a sliding and fluid-tight seal with the wall 1240 of the end cap 124. The Teflon caps 222 are positioned at the sliding interfaces between the members to provide a good fluid-tight seal and to prevent grabbing or binding of the sliding surfaces.

The valve is a multi-purpose piston valve and can be biased in either a normally shut-off or a normally open position, or it can be changed so that itis not biased to either position. To bias the piston 200 into a shut-off position, the spring 300 is positioned in between the stop 210 and the stop 127. In this manner, the spring closes the piston 200 to the left as shown in the figure, causing the end 200a of the piston to seal against the in side surface 120a and prevent fluid flow from the passages 122 into the interior passage 204 of the piston. To bias the piston to a normally open position, the spring 300 is merely positioned in between stops 210 and the stop 114'. It will be apparent that under these conditions, the spring will tend to bias the piston to the right as shown in the drawing against the piston stop l24b in the end cap 124. A second control port 134 having a threaded exterior end extends into the housing from the exterior of the tubular sidewall into the annular groove 226. Air pressure applied in the control port 134 acts against the ring-shaped stop 210 actuating the piston to the right as shown in the drawing.

Consider now the operation of the niulti-purpose piston valve. Assume that the spring 300 is positioned as shown in the drawing in between the spring stops 127 and 210. Under these conditions, the spring 300 biases the piston to the left to a shut-off position, causing a seal between the end 200a of the piston and the inner surface a. With such an arrangement, high pressure input to the valve is connected to the threaded input of the port 118 and the lower pressure outlet is connected at the threaded port 219. Under these conditions, fluid pressure passes through the passages 122 and acts inwardly around the outer surface of the tube 202, and no pressure is extended, tending to actuate the piston.

Assume now that pneumatic pressure is applied to the control port 134. The control pressure acts in between the opposing surfaces of the stops 210 and 1 14, the O-ring seals 220 and 222 acting to prevent any of the control pressure from leaking out. around the stops 1 14 and 210. As a result, the control pressure acts on the stop 210, forcing the piston 200 to the right, as shown in'the drawing, into an open position where the end 2000 of the piston is separated from the inner wall 1200. Under these conditions, the fluid at the input port 118 passes through the passages 122 into the passage 204 through the piston to the port 119. When the pneumatic pressure is removed from the control port 134, the spring 300 acts in between the stop 210 and 128, actuating the piston back to a closed position.

Assume now that it is desired to bias the piston to an open position. To facilitate this change, the end cap 124 is screwed out from the tubular sidewall 110 and the spring and piston removed by sliding out from the tube 110 to the right as shown in the drawing. The spring 300 is then positioned back in the annular groove 126 of the stop 114 and the piston 200 is slid back into the tubular sidewall 110 in the same orientation as shown in the drawing. The end cap 124 is then screwed back into the tubular sidewall 110. When used as a normally shut-off valve, the high pressure input is applied to the passage 119. Under these conditions, the pressure flows through the inside of the tube 202 and has no tendency to force the piston 200 to a shut-off position.

Assume now that it is desired to actuate the piston to a shut-off condition. A pneumatic control pressure is applied to the control port 132. A pneumatic control pressure acts in between the stops 210 and 127 against the pressure of the spring 300 causing the piston 200 to be actuated to the left so that the end 200a forms a seal against the surface 120a and thereby shuts off fluid flow through the valve. By releasing the pneumatic pressure from the control port 132, the spring 300 (now positioned inbetween the stops 114 and 210) actuates the piston 200 back to the right so that the end 200b is again against the stop 124!) formed in the end cap 124. 1

Several features of the valve should be carefully noted. First, the spring stops 114, 210 and 127 are spaced apart in such a position so that regardless of the position of the piston 200, whether in a closed or open position, space is provided for the compressed coil spring 300. Additional space is advantageously provided for the spring due to the annular grooves 126, 214 and 128. It should also be noted that the control ports 134 and 132 enter the inside of the tubular sidewall 110 at positions which are on opposite sides of the sliding stop 210 regardless of whether the piston 200 is in a shut-off or open position. As a result, there is no need to take special care in actuating the piston to prevent the piston from making its full axial movement in the housing.

Preferably, all of the housing 100 parts, except for 0 rings 220, 222 and 224, are made of a plastic material that is resistant to corrosive acids, etc'. passed therethrough. The spring 300 may be made of conventional metalsas it is sealed off from' the chamber 112.

What has been shown then, is a multi-purpose piston valve, and a preferred embodiment of the invention has been disclosed. It will be understood by those skilled in the art that otherv rearrangements of the valve will be evident to those skilled in the art within the scope of the following claims.

What is claimed is: A 7

v1. A controllable, two-way fluid shut-off valve convertible to three normal operating states comprising:

a. a housing comprising:

l. a tubular side wall defining a chamber elongated between first and second chamber ends;

2. a first ring-shaped spring stop affixed in sealing relation around the inside of said side wall in said chamber, spaced away from'and adjacent to said first chamber end;

3. an end cap connected to said side wall at the first end of said chamber and comprising a first exterior accessable port, a separating wall positioned in between said first port and said chamber and at least one passage between said chamber and said first port;

. an end cap removably affixed to said side wall at the second end of said chamber and comprising a second ring-shaped spring stop extending into said chamber and a second port extending from said chamber to the exterior;

b. a removable tubular-shaped, shut-off piston elon-' gated between first and second ends and mounted in said chamber, said piston comprising a ringshaped third stop affixed in sealing arrangement around the piston and intermediate the ends thereof, said piston having the second end thereof slidably .mounted in said second port and the first end adapted for sealing engagement with said separating wall, said passage entering said chamber on the outer side of said piston, the piston being slidable between a shut-off position against said separating wall and an open position spaced away from said separating wall, said first, second and third spring stops being positioned and constructed to leave space for a compressed bias spring on either side of said third stop when said piston is in said open or said shut-off position;

. separate ring-shaped means provide a sliding fluid seal in between said third stop and the inside of said side wall, in between said first stop and said piston and in between said second port and said piston; and

. first and second pneumatic control ports, respectively, passing through said housing to said chamber at positions which are at opposite sides of said third stop whether said piston is in said shutoff or said open position, pneumatic pressure applied in one of said control ports acting against one side of said third stop for actuating said piston to said shut-off position and pneumatic pressure applied in the other of said control ports acting against the other side of said third stop for actuating said piston to said open position.

2. A valve according to claim 1 wherein said first stop comprises a ring-shaped extension of said sidewall and a ring-shaped recess therein opening toward said third stop for the receipt of one end of a coil spring.

3. A valve according to claim 1 wherein said second stop comprises a ring-shaped recess in said second end cap opening toward said third stop for the receipt of one end of a coil spring.

4. A valve according to claim 1 wherein one of said pneumatic control ports extends through said second end cap from the outside thereof to said chamber.

5. A valve according to claim 3 wherein one of said pneumatic control ports extends through said second end cap from the outside thereof to said recess in said second end cap.

6. A valve according to claim 2 wherein one of said control ports extends through said sidewall and through said first stop to the recess in said first stop.

7. A valve according to claim 2 wherein said second stop comprises a ring-shaped recess in said second end cap opening toward said third stop for the receipt of one end of a spring coil, one of said pneumatic control ports extending through said sidewall and said ringshaped exterior to the recess therein and wherein the other of said pneumatic control ports extends through said second end cap to said recess comprising said second stop.

'al a: t 1 1r 5 

1. A controllable, two-way fluid shut-off valve convertible to three normal operating states comprising: a. a housing comprising:
 1. a tubular side wall defining a chamber elongated between first and second chamber ends;
 2. a first ring-shaped spring stop affixed in sealing relation around the inside of said side wall in said chamber, spaced away from and adjacent to said first chamber end;
 3. an end cap connected to said side wall at the first end of said chamber and comprising a first exterior accessable port, a separating wall positioned in between said first port and said chamber and at least one passage between said chamber and said first port;
 4. an end cap removably affixed to said side wall at the second end of said chamber and comprising a second ring-shaped spring stop extending into said chamber and a second port extending from said chamber to the exterior; b. a removable tubular-shaped, shut-off piston elongated between first and second ends and mounted in said chamber, said piston comprising a ring-shaped third Stop affixed in sealing arrangement around the piston and intermediate the ends thereof, said piston having the second end thereof slidably mounted in said second port and the first end adapted for sealing engagement with said separating wall, said passage entering said chamber on the outer side of said piston, the piston being slidable between a shut-off position against said separating wall and an open position spaced away from said separating wall, said first, second and third spring stops being positioned and constructed to leave space for a compressed bias spring on either side of said third stop when said piston is in said open or said shut-off position; c. separate ring-shaped means provide a sliding fluid seal in between said third stop and the inside of said side wall, in between said first stop and said piston and in between said second port and said piston; and d. first and second pneumatic control ports, respectively, passing through said housing to said chamber at positions which are at opposite sides of said third stop whether said piston is in said shut-off or said open position, pneumatic pressure applied in one of said control ports acting against one side of said third stop for actuating said piston to said shut-off position and pneumatic pressure applied in the other of said control ports acting against the other side of said third stop for actuating said piston to said open position.
 2. a first ring-shaped spring stop affixed in sealing relation around the inside of said side wall in said chamber, spaced away from and adjacent to said first chamber end;
 2. A valve according to claim 1 wherein said first stop comprises a ring-shaped extension of said sidewall and a ring-shaped recess therein opening toward said third stop for the receipt of one end of a coil spring.
 3. A valve according to claim 1 wherein said second stop comprises a ring-shaped recess in said second end cap opening toward said third stop for the receipt of one end of a coil spring.
 3. an end cap connected to said side wall at the first end of said chamber and comprising a first exterior accessable port, a separating wall positioned in between said first port and said chamber and at least one passage between said chamber and said first port;
 4. an end cap removably affixed to said side wall at the second end of said chamber and comprising a second ring-shaped spring stop extending into said chamber and a second port extending from said chamber to the exterior; b. a removable tubular-shaped, shut-off piston elongated between first and second ends and mounted in said chamber, said piston comprising a ring-shaped third Stop affixed in sealing arrangement around the piston and intermediate the ends thereof, said piston having the second end thereof slidably mounted in said second port and the first end adapted for sealing engagement with said separating wall, said passage entering said chamber on the outer side of said piston, the piston being slidable between a shut-off position against said separating wall and an open position spaced away from said separating wall, said first, second and third spring stops being positioned and constructed to leave space for a compressed bias spring on either side of said third stop when said piston is in said open or said shut-off position; c. separate ring-shaped means provide a sliding fluid seal in between said third stop and the inside of said side wall, in between said first stop and said piston and in between said second port and said piston; and d. first and second pneumatic control ports, respectively, passing through said housing to said chamber at positions which are at opposite sides of said third stop whether said piston is in said shut-off or said open position, pneumatic pressure applied in one of said control ports acting against one side of said third stop for actuating said piston to said shut-off position and pneumatic pressure applied in the other of said control ports acting against the other side of said third stop for actuating said piston to said open position.
 4. A valve according to claim 1 wherein one of said pneumatic control ports extends through said second end cap from the outside thereof to said chamber.
 5. A valve according to claim 3 wherein one of said pneumatic control ports extends through said second end cap from the outside thereof to said recess in said second end cap.
 6. A valve according to claim 2 wherein one of said control ports extends through said sidewall and through said first stop to the recess in said first stop.
 7. A valve according to claim 2 wherein said second stop comprises a ring-shaped recess in said second end cap opening toward said third stop for the receipt of one end of a spring coil, one of said pneumatic control ports extending through said sidewall and said ring-shaped exterior to the recess therein and wherein the other of said pneumatic control ports extends through said second end cap to said recess comprising said second stop. 